1-halo-6-alkoxy-4-methylhexadiene-2, 4 and preparation thereof



Jan. 1, 1952 M. s. NEWMAN 2,581,284 lHALO6-ALKOXY4-MET HYLI-IEXADIENE-2,4 AND PREPARATION THEREOF orlginal Filed May 10, 1947 3 Sheets-Sheet l HYDROLYZED WITH AMMONIUM CHLORIDE SOLUTION- I SEPARATED-CONCENTRATED-D|STILLED I IiMETHOXY-4-METHYLHEXYNE-Z-DIOL-LT] DISSOLVED IN ALCOHOL-REDUCED UNDER LOW HYDROGEN PRESSURE USING PALLADIUM ON CHARCOAL CATALYST- FILTERED-SOLVENT REMOVED- RESIDUE DISTILLED UNDER REDUCED PRESSURE Ifl/IETHOXY-4-METHYLHEXYNE-Z-DIOL-LTI IDISSOLVED IN PYRIDINE'AND ADDED T O COLD ACETIC ANHYDRIDE SOLVENTS REMOVED BY DISTIL LATION.FRACTIONATED ILACETOXY-4-HYDROXY-G-METHOXY-4-METHYLHEXENEII DISTILLED UNDER VACCUUM EVACUATED-DISTILLED- FRACTIONATED MIXED WITH POTASSIUM ACID SULPHATE- WITH INERT ATMOSPHERE- IlAGETOXY-6-METHOXY-4 METHYLHEXADIENE-2T] MIXED WITH SODIUM METHOXIDE AND METHANOL- REMOVED BY DISTILLATION-WATER,HYDROCHLORIC ACID AND ETHER ADDED-AQUEOUS LAYER EXTRACTED WITH ETHER-WASHED WITH SODIUM BICARBONATE SOLUTION-ETHER REMOVED BY DISTILLATION. RESIDUE DISTILLED UNDER VACCUUM I EIYDROXY-G-METHOXY-4-METHYLHEXADIENE-2? REFLUXED-METHANOL ANHYDROUS PYRlDINE-TAKEN UP WITH WATER- CHLORIC ACID-EXTRACTED WITH ETHER l-CHLORO- 6 METHOXY'4-METHYLHEXADIENE-ZI' FIG. 1

lNVE/VTOR MELVIN SPENCER NEWMAN M IZOX Jan. 1, 1952 5, NEWMAN 2,581,284

l-HALO-B-ALKOXY-l-M ETHYLHEXADIENE-2-,4 AND PREPARATION THEREOF Original Filed May 10, 1947 v5 Sheets-Sheet 2 CICH2CVH=CH'C=CH'CH2OCH3 C|H3 HOCH2CH=CH-C=CH-CH2OCH3 CH3 II I CH3COCH2CH=CH-C=CHCH2OGH3 FIG 8' m ICH2CH=CH-C=CH--CH2OCH3 'm/vE/vrw? MELVIN SPENCER NEWMAN Jan. 1, 1952 2,581,284

M. S. NEWMAN l-HALO-6-ALKOXY-4METHYLHEIXADIENE-2,4

AND PREPARATION THEREOF Original Filed May 10, 1947 3 Sheets-Sheet 3 PROPARGYL ALCOHOL+ BUTYLMAGNESIUM CHLORIDE +4-METHOXYBUTANONE-2 HYDROLYZED WITH AMMONIUM CHLORIDE SOLUTION SEPARATED-CONCENTRATED-DISTILLED 6-METHOXY-4-METHYLHEXYNE-Z-DIOL-1, 4

[LSSOLVED m PYRlDlNE-ACETIC ANHYDRIDE ADDED- DISTILLEFI IiACETOXY- I-HYDROXY-S-METHOXY-4-METHYLHEXYNE- I MIXED WITH CRUSHED POTASSIUM ACID SULPHATE-DISTILLED-FRACTIONED l AcEToxY-s-ms'rl-loxY-4-METHYLHEXENE-4-YNE3I ON OF SODIUM METHOXIDE IN I ADDED TO SOLUTI OL-ORGANIC PRODUCT ISOLATED ABSOLUTE METHAN IiHYDROXWS-METHOXY-I-METHYLHEXENE-4-YNE-fl REDUCTION UNDER LOW HYDROGEN PRESSURE USING PALLADIUM ON CHARCOAL CATALYST IN ABSOLUTE ALCOHOL l-HYDROXY-G-METHOXY-4-METHYLHEXADIENE- 2,7]

DISSOLVED IN PYRIDINE-ADDED TO MIXTURE OF THIONYL CHLORIDE AND ANHYDROUS PYRIDINE-TAKEN UP WITH WATER-ACIDIFIED WITH HYDRO- CHLORIC ACID-EXTRACTED WITH ETHER-WASHED-FILTERED I l-GHLORO-6-METHOXY-4-METHYLHEXADIENE-2,4

INVENTOR 9 MELVIN SPENCER NEWMAN- Patented Jan. 1, 1952 UNITED STATES PATENT OFFICE 1-HAL0-G-ALKOXY-I-METHYLHEXADIENE- 2,4'AND PREPARATION THEREOF I Melvin S. Newman, Columbus, Ohio, assignor to The Ohio State University Research Foundation, Columbus, Ohio, a corporation of Ohio Original application May 10, 1947, Serial No. 747,176. Divided and this'application Novem-. her 9,- 1950, Serial No. 194,858

Claims. (01. 260414) V This application is a divisional application of and R represents alowe'r alkyl radical having not.

my copending application Serial No. 747,176, more than six carbon atoms.

filed on May 10, 1947, now Patent No. 2,555,5992 Further objects of my invention are the syn-f This invention relatest inew compounds or th of :new --1-ha logen-4-methylhexadienes, compositions of matter useful as intermediates 5 new l-a cyloxy -fl -methy-1hexadienes, and new in the synthetic roduction of vitamin A ethers l-hydroxy-4-methylheXadieneS; and the prod ar mpounds and to processes for syn vision of new methods of synthesizing such new thesizing such new compounds. It is illustrated compounds; I y

y processes f forming ydr Xy-6- y- Further objects and advantages of the present m thy1h X diene-2,4 and its esters of organic 1o invention will be apparent from the following deacids and halogen acids. Examples of such orscription, reference-being had to the accompany ganic' acid esters are the acetate, propionate, ing drawings wherein preferred forms of embo f butyrate, trimethylacetate and benzoate. Examments of the inventionare clearly shown.

ples of such halogen acid esters are 1-iodo-6- In the drawings: methoxy 4 methylhexadiene 2,4, 1 ch1oro-6- Fig. 1 illustrates amethod of synthesizing some methoXy-4-methylhexadiene-2,4 and l-bromo-fiof the substances selected in illustration of my methoxyl-methyl-hexadime-2,4. invention, the substances and methods shown- The specific hydroxy alkoxy methylhexeneconstituting some of the preferred embodiments ynes which I have synthesized have all had althereof;

Y DS- Fig. 2 shows the structural formula of a chloro- By use of the word alkoxy in the last senalkoxymethylhexadiene which may be synthetence, elsewhere in this specification and in the sized by my process;

claims, I meana compound having an alkyl rad- Fig. 3 shows the structural formula of a hy-' ical attached to the remainder of the molecule droxyalkoxymethylhexadiene which may be synby oxygen where the alkyl radical has not more thesized by my process;

than six carbon atoms and we so define the Fig. 4 shows the structural formula of an acylterm alkoxy herein. Compounds having an oxyalkoxymethylhexa'diene which may be synalkyl group with more than four carbon atoms thesized by my process;

but not more than six carbon atoms are operative Fig. 5 shows the structural formula of an acyland compounds having such an alkyl group with oxyhydroxyalkoxymethylhexene which may be more than six carbon atoms may be operative but synthesized by my process;

in later manipulations, the compounds involved Fig. 6 shows the structural formula of an alkmay be moredifiicult to handle due to the higher oxymethylhexene-diol which may be synthesized temperatures necessary. by my process;

Prior to my discoveries, there has been no rec- 3 Fig. 7 shows the structural formula of a bromoognized method of preparing the above mentioned alkoxymethylhexadiene which may be synthecompounds. Nor had these materials been presized by my process;

viously synthesized norisolated. Fig. 8 shows the structural formula of an iodo- One of the objects of my invention is the proalkoxymethylhexadiene which may be synthesized duction of new intermediate chemical compounds 40 y my p and useful in the synthesizing of vitamin A ethers; Fig. 9 shows an alternate method of synthesizs imilar compounds, and other chemicals, ing some of the 4-methylhexadienes-2,4, illus- Another object of my invention is the provision trated in the other figures.

of new methods of synthesizing various interme- In general, the processes covered hereby relate diates and other chemicals. to the synthesis of l-hydroxy-6-alkoxy-4- A further object of my invention is the promethylhexadienes-2,4 and its esters. One methvision of new methods for synthesizing -method comprises the dehydration of l-acyloxylylhexadienes-2,4. hydroxy-6-alkoxy-4-methylhexene-2; alcoholiz-i A further object is the'synthesis of new coming the resulting 1 acyloxy-G-alkoxy-4-methylpounds of the formula 59 hexadiene-2,4 to a 1 hydroxy 6 alkoxy 4- methylhexadiene-2,4; and then reacting with a suitable halogen acid derivative to formhalogen esters (a1kylhalides) --The l-acyloxy-G-alkoxywhere Y represents a-member of the group 'com- 4methy1hexadiene-2,4-is an ester of the l-hyprising hydroxyl and esters of a hydrgxyl group 5 droxyi-6ealkoxye4;methylhexadiene-2,4 asarethe methyl-hexadiene-2,4; and then reacting with a suitable halogen acid derivative to form the corresponding halogen ester (alkyl halide) The dehydration of the 1-acyloxy-4-hydroxy- 6 alkoxy 4 methylhexene-Z may be accomplished by heating with a suitable dehydrating agent such as, for example, potassium acid sulfate or phenyl isocyanate or other isocyanates in a vacuum or in the absence of oxygen or in an inert atmosphere, the distillate being collected in fractions and used as such or fractionated again if desired.

The alcoholysis of the l-acyloxy-fi-alkoxy-- methylhexadiene-2A may be accomplished by heating with a metal alcoholate in an anhydrous alcohol solution and isolating and purifying. Preferably, the metal alcoholate is prepared from the same alcohol as is used as .a solvent, the metal alcoholate serving as a catalyst. For example, I may use corresponding sodium, calcium or aluminum alcoholates in methanol, ethanol, a propanol or a butanol.

The halogen estersmay be preparedby reacting the i-hydroxy-6-alkoxy-4-methylhexadiene- 2,4 with a halogen containing acid derivative such as thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus tribromide and phosphorus pentachloride in an inert solvent in the presence of a tertiary amine acid-binding agent such as pyridine, the picolines, the lutidines, quinoline, the dialkyl anilines, or the trialkyl amines. To prepare the corresponding iodide, I prefer to replace the bromine or chlorine by refluxing with an inorganic iodide such .as'sodium iodide or potassium iodide in an acetone solution (i. e. a standard iodide exchange).

The reduction of the l-hydroxy-fi-alkoxy-lmethylhexene-4-yne-2 to the corresponding 1- hydroxy-6-alkoxy-4-methylhexadiene-2A may be accomplished either by a chemical reduction such as by solution in alcohol with a .zinc copper alloy or by the use of hydrogenand a catalyst such as a supported palladium catalyst or a Raney iron catalyst.

In certain of the steps described, a caution has been given against the presence of oxygen. It is clusive, show the reactions involved in the example illustrated in Fig. 9; and Equations 15-18, inclusive, suggest several specific examples of the various ways by which I may synthesize the compounds of Figs. '7 and 8.

(2) ClMgOGHr-CEC-MgCl CHaC O-C Hz-CHq-0 CH5 on, car ocm-ozcJz-cm-cm-ocm MgCl (3) CH: ClMgOCHaCEC-(J-CflgCHiOCH: 21110 MgCi CH3 Hocmczc-d -omom-ocm 2ClMg0H (4) CH3 nocn,c-Ec-dcmomocm H2 CH: HOCHiCH=CH+( ,CHCHiOCHa (5) CH: noonion=cn-e cmcmooni rcnioono 0 on; g I cm oon,on=oH-d-on=omoOH; CHsQO on "5) 0 CH5 cHa-li-ooH,cH=oH-o omcm0om 3 0 CH3 card-o omon=cn-d=cnomocn= mo 7 0 on; cm- -ocmcmoH-cwnomooni+onaon CH; noomcn==cm-d=onomoora CHaC-OOCHa (a) on: nocniomon-bmnomoonfi-soo11+oiHiN 1. Reaction HOCHzCECH 2OHsCH,CH;CH:MgCl 013 0 0021 011 0011;

2. Hydrolysis to be emphasized that should be avoided in scribed.

One specific example of each of the two methods explained above for the synthesis of a 1-hydroxy-6-alkoxy-4-methylhexadiene 2,4 is illustrated in the accompanying drawings of Figs. 1 and 9. These specific examples are, however, merely illustrative and are not to be considered as constituting the invention covered hereby. The reactions involved in the specific examples illustrated in Figs. 1 and 9 and referred to in this paragraph are as follows. Equations 1-8, inclusive, show the reactions involved in the example illustratedin Fig. 1; Equations 9-14. in-

the presence of oxygen all of the processes de- 12 on. I: NaOCHa onro-o-om-ogo- =cH-oH,-ooH.+omoH BrCH2CH=CH=CH.CHzOCH CaCh The preparation of 1-acyloxy-4-hydroxy-6- alkoxy-4-methylhexene-2 is not described in detail nor claimed in this application. Itis so described and is claimed in copending application Serial No. 747,179, now Patent No. 2,555,989. However, as stated above, in order to completely disclose at least one example of my method of forming a 1-hydroxy-6-alkoxy-4-methylhexadiene-2,4 involving the forming of such a compound as an intermediate, I have shown herein one method of synthesizing l-acetoxy-l-hydroxy-6methoxy4-methylhexene-2 which is a. specific example of a 1-acyloxy-4-hydroxy-6-alkoxy-4-methylhexene-2.

:Nor is the preparation of a 1-hydroxy-6-alkoxy-4-methylhexene-4-yne-2 described in cletail in this application. It is so described and is claimed in copending application Serial No. 747, 177. However, at least one example of my method of forming a 1-hydroxy-6-alkoxy-4-methylhexadiene-2,4 involving the forming of such a compound as an intermediate, I have shown herein one method of synthesizing a 1 hydroxy-6-methoxy-4-methylhexene-4-yne-2. In general the illustrated process of synthesize ing 1 acetoxyl-hydroxy-S-methoxyA-methylhexene-2 comprises the reaction of propargyl alcohol with butylmagnesium chloride to form a complex reagent and the reaction thereof with 4-methoxybutanone-2; the hydrolyzation thereof to produce a 6-methoxy-4-methylhexyne-2- diol-l,4; the reduction of the methylhexynediol and the distillation of the products to produce 6-rnethoxy-4-methylhexene-2-diol-1,4; the reaction of the-methylhexene-diol with acetic anhydride and the distillation of the product to produce a 1-acetoxy-4-hydroxy-6-methoxy-4-meth-- ylhexene-Z.

in order to completely disclose In general the illustrated process of'synthesizing 1 hydroxy 6-methoxy-4-methylhexene-4- yne-Z, comprises, the formation of a complex organo-metallic reagent by the reaction of propargyl alcohol with butylmagnesium chloride; to-form a complex, organo metallic reagent; the reaction of the reagent thus formed with 4-methoxybutanone-Z; the hydrolyzation of the resultant compound to produce a6-methoxy-4-methylhexyne-2-diol-1,4; the reaction of the methylhexynediol with acetic anhydride and distillation of the products. to produce l-acetoxy l-hydroxy- 6-methoxy-4-methylhexyne-2; the dehydration of the acetoxyhydroxymethoxymethylhexyne with potassium acid sulfate to produce 6-methoxy-4-methylhexene-4-yne-2; and the alcoholysis of this product with sodium methoxide in methanol to produce l-hydroxy-B-methoxy- 4-methylhexene-4-yn'e-2.

'Ihe followingExamples I to V, inclusive, are presented in illustration ofmy, invention.

EXAMPLE-I Preparation of "Dz'erze-ol acetate (l-acetomy-G- methoxy-4-methylhexadiene-2,4)

Fraction Vapor Temp. Bath Temp. Pressure Wt. as" m M a g. 1 74-77. 8 101-102 1. 0' l. l 1. 4615 2 77. 881 102-107 1. 0 6. 3 1. 4711 The main fraction, 6.3 g. of viscous yellow oil, amounted to a yield of 69% of theoretical.

Neutral equivalent0bserved: 188.2; Calcd:184.0.

Analysis-Calcd. for C10H1s0 C, 65.2; H, 8.8. Found: C, 65.5; H, 8.9.

The structural formula of the product is:

P CH3 GradooH2-oH=cH J=oH oH,o0H,

EXAMPLE II Preparation of "Dz'ene-ol (Z-hydroxy-G-methomy-el-methylhea'adie'ne-2,4)

In a 200 m1. round-bottomed flask fitted with a ground-in condenser holding a calcium chloride tube in the top, were placed 11.6 g. (0.06 mole) of diene-ol acetate (l-acetoxy-fi-methoxy-4-methylhexadiene-2,4), 2.7 g. (0.05 mole) of sodium methoxide, and "m'l. (2.47 mole) of absolute methanol. The mixture was refluxed for five hoursjduring which time it turned brown. By distillation, 30 ml. of methanol was then removed.

To the reaction mixture were added 100 ml. of water, 1'7 ml. of concentratedhydrochloric acid, and 90 ml. of ether. After separation of the other layer, the aqueous layer was' 'extra'cted with ml. of ether in small portions.

The combined ether extracts were then washed with m1. of saturated sodium bicarbonate solution. The ether layer was. dried .overanhydrous a l-acetoxy-l crushed poarranged forv calcium suliate, the ether'removed by distillation at atmospheric pressure and the residue distilled under vacuum, introducing illuminating gas through the capillary tube.

Fraction Vapor Temp. Bath Temp. Pressure Wt. 11

degrees ddgrecs mm. :1.

Fraction 2'(3.9 g.) represented a yield oi 43.6% of theoretical.

'hnalysis -Calcd. for CaHmOz: Found: 0,657.3; H, 10.0.

Calculated i Observed EXAMPLE III Preparation of Diem-chloride (i-chloro-dmethomy-4-1nethyZhe:cadiene-2,4)

A mixture of 3. 1 ml. (0.0046 mole) of purified thionyl chloride and 2.4 ml. of anhydrous pyridine wasplaced in a 25 ml. Erlenmeyer flash, which f was stoppered and cooled in an ice bath. To this mixture, by means of a medicine dropper, was added a solution of 6.0 g. (0.042 mole) diene-ol (l hydroxy-6-methoXy4-methylhexadiene-2,4l dissolved in 2.0 ml. of anhydrous pyridine, making a total of 4.4 ml. (0.055 mole) of pyridine.

Aiter standing in ice water for four hours, the contents of the flask were taken up in 30 ml. of cold water, and acidified with 2 ml. of concentrated hydrochloric acid.

The brown oil which formed was extracted with 100 ml. of ether and the ether layers washed cautiously with 60 ml. of saturated sodium bicarbonate soluticn. The ether solution was filtered through anhydrous sodium sulfate and treatedwith anhydrous calcium sulfate.

The ether was removed under vacuum and the residue distilled from a 10 ml. Claisen flash, introducing illuminating gas through the capillary tube.

Fraction Vapor Temp. Bath Temp. Pressure. 2 Wt. ne

degrees degrees 7 mm 0. l -61 72-82 1. 5 l. 2 l. 4919 2. i i 61. 5-66 83-96 1. 5 1. 6 1. 4980 Residual tar.

Fraction 2 (1.6 g.) amounted to a 23.6% yield. Analysis: Calcd. for CaHmOCl: C, 59.81; H, 8.16; Cl, 20.94. Found: C, 60.33, 60.23; H, 8.35, 8.31; Cl, 20.94, 21.25.

The structural formula of the product is:

EXAMPLE IV Preparation of 1 bromo-ti-methoxy-sl methylheradiene-2,4

Four and nine-tenths m1. of PBrz (phosphorus tribromide) was added dropwise with stirring to a solution of 18 g. of l-hydroxy-G-methoxy-dmethylhexadiene-ZA and 3.4 ml. of pyridine, keeping the temperature of the reactants at 10 C. during the addition by means of an ice-salt bath. After the addition had been completed, the reaction mixture was stirred for 4-5 minutesat -l0 C.; for 45 minutes at room temperature;

Preparation of 1-hydroa:y-6-methoa:y-4-methylhexadiene-ZA This compound was prepared by reducing 0.7 g. of 1 hydroxy-ES-methoxy-4-methylhexone-4- yne-2 under low hydrogen pressure using a palladium-on-charcoal catalyst in absolute alcohol.

After one equivalent of hydrogen was taken up,"

the absorption ceased. The catalyst was removed by filtration, the alcohol solvent removed and the residue distilled at -7 0 pressure. Yield=0.5 g.

The product was characterized by a solid p-nitrophenyl urethan derivative, M. P. 116-118" C. The product has the following structural formula:

. 0H HOGH;CH=CHC=CHCHAOCH3 Analysis 1 Calculated Found 5.88 5. so, 5. 65V 0.15 9.70, 9.60

While the forms of embodiments of the present invention as herein disclosed constitute preferred forms, it is to forms might be adopted, scope of the claims which follow.

Iclaim:

l. A new composition of matter consisting of 1 halo-B-methoxy-4-methylhexadiene-2,4, where the halo atom is selected from the group consisting of the chloro and iodo.

2. A new composition of matter consisting of 1 chloro-B-methoxy-4-methylhexadiene-2,4.

3. A new composition of matter consisting of liodo-S-methoxy-4-methylhexadiene-2,4.

4. A process of preparing a l-halo-G-alkoxylmethylhexadiene-l l which comprises reacting a l-hydroxy-fi-alkoxy 4 methylhexadiene 2,4 with an inorganic acid halide selected from the class consisting of thionyl chloride, thio'nyl bromide, phosphorus trichloride, phosphorus tribromide and phosphorus pentachloride in the presence of a tertiary amine acid-binding agent was obtained. The

C. under 1 mm.

be understood that otherall coming within the selected from the class consisting of pyridine, the picolines, the lutidines, quinoline, the dialkyl anilines and the trialkyl amines.

5. A method of preparing a 1-ha1o-6-alkoxy-4- methylhexadiene-2A which comprises the steps of mixing a thionyl halide and anhydrous pyridine; adding a solution of l-hydroxy-fi-alkoxy-lmethylhexadiene-2A in anhydrous pyridine; acidifying the resultant products with concentrated hydrochloric acid; extracting a portion of the products with ether; washing the extracted portion with a sodium bicarbonate solution; fi1- tering; drying; removing the ether; and distilling the residue. 1

6. A method of preparing a 1-halo-6-alkoxy-4- methylhexadiene-2,4 which comprises the steps of mixing a thionyl halide and anhydrous pyridine; adding a solution of 1-hydroxy-6-alkoxy-4- methylhexadiene 2,4; acidifying the resultant products; extracting a portion of the products; and distilling.

7. A method of preparing a 1-ha1o-6-a1koXy-4- methylhexadiene-2,4 which comprises the steps of mixing a thionyl halide and anhydrouspyridine; adding a solution of 1-hydroxy-6-alkoxy-4- methylhexadiene-2,4; acidifying the resultant products; extracting a portion of the products; washing the extracted portion; and distilling the residue.

8. A method of preparing a 1-halo-6,-alkoxy-4- methy1hexadiene-2,4 which comprises the steps of 10 mixing a thionyl halide and anhydrous pyridine;

and adding a solution of 1-hydroxy-6-alkoxy-4- methylhexadiene-2,4.

9. A method of preparing a 1-halo-6-alkoxy-4- methy1hexadiene-2,4 which comprises the steps of mixing a thionyl halide and anhydrous pyridine; adding a solution of l-hydroxy-fi-alkoxy-lmethylhexadiene-2,4; and acidifying the resultant products.

10. A method of preparing a 1-ha1o-6-alkoxy-4- methylhexadiene-2,4 which comprises the steps of mixing a thionyl halide and anhydrous pyridine; adding a solution of l-hydroxy6-'alkoxy-4- methylhexadiene-2,4 in anhydrous pyridine; acidifying the resultant products; and distilling the residue.

MELVIN S. NEWMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Oroshnik Feb. 13, 1951 OTHER REFERENCES Number 2,541,091

so November 1, 1949, in Official Gazette, Volume 628. 

1. A NEW COMPOSITION OF MATTER CONSISTING OF 1HALO-6-METHOXY-4-METHYLHEXADIENE-2,4 WHERE THE HALO ATOM IS SELECTED FROM THE GROUP CONSISTING OF THE CHLORO AND IODO.
 4. A PROCESS OF PREPARING A 1-HALO-6-ALKOXY-4METHYLHEXADIENE-2,4 WHICH COMPRISES REACTING A 1-HYDROXY-6-ALKOXY - 4 - METHYLHEXADIENE - 2,4 WITH AN INORGANIC ACID HALIDE SELECTED FROM THE CLASS CONSISTING OF THIONYL CHLORIDE, THIONYL BROMIDE, PHOSPHORUS TRICHLORIDE, PHOSPHORUS TRIBROMIDE AND PHOSPHORUS PENTACHLORIDE IN THE PRESENCE OF A TERTIARY AMINE ACID-BINDING AGENT SELECTED FROM THE CLASS CONSISTING OF PYRIDINE, THE 